1. Field of the Invention
The present invention relates to a magnetic transfer master disk, its manufacturing method and a magnetic transfer method. More particularly, the present invention relates to a magnetic transfer master disk which is suitable for transferring magnetic information such as format information to a magnetic disk used in a hard disk device and the like, and also relates to a method for the manufacturing magnetic transfer master disk and a magnetic transfer method.
2. Description of the Related Art
Generally, a magnetic disk (hard disk) used in a hard disk drive which has become popular rapidly in recent years, is once delivered from a magnetic disk maker to a drive maker, and thereafter format information and address information are written in the magnetic disk before it is incorporated in the hard disk drive. The writing operation can be performed by using a magnetic head, but a method for collectively performing transfer from a master disk in which format information and address information are written, is efficient and preferred.
In the magnetic transfer method for collectively performing transfer in a state where a master disk and a disk to be transferred (slave disk) are brought into close contact with each other, the magnetic field generating device such as an electromagnet device and a permanent magnet device is provided on one face or both faces of the disks in close contact with each other, so that information (for example servo signal) provided for the master disk is transferred to the slave disk by applying a transfer magnetic field. Here, in order to accurately perform the magnetic transfer, it is extremely important to make the master disc closely contact with the slave disk uniformly without a gap.
As the master disc used for the magnetic transfer method, as disclosed in Japanese Patent Application Laid-Open No. 2001-256644, a disk in which a protruding and recessed pattern corresponding to an information signal is formed on the surface of a substrate and in which a magnetic layer is applied on the surface of the protruding and recessed pattern, is normally used. The magnetic transfer master disk is generally produced through a electroforming process for applying electroforming to an original plate on which information is formed by a protruding and recessed pattern and for laminating a metal plate composed of an electroforming layer on the original plate so as to make the protruding and recessed pattern transferred on the surface of the metal plate, through exfoliating the metal plate from the original plate, through a punching process for punching out the exfoliated metal plate into a predetermined size, and thereafter through a process for applying a magnetic layer on the surface of the protruding and recessed pattern.